JPH05190032A - Film forming method for transparent conductive film - Google Patents

Abstract

PURPOSE:To provide a transparent conductive film, film thickness is uniform and the resistivity distribution of which the is even. CONSTITUTION:When a transparent conductive film is formed on a substarate 1 by means of a DC magnetron sputtering device, a shielding plate 4 opposing to the erosion region 8 on a target 5 is arranged in the space defined between the substrate 1 and the target 5. The shielding plate 4 is composed of an inorganic shielding plate and an organic coat adhered to the surface opposing to the target 5 of the inorganic shielding plate. When the transparent conductive film is formed on the substarate 1 by means of the DC magnetron sputtering device, the shileding plate 4 opposing to the erosion region 8 on the target 5 is arranged in the space defined between the substrate 1 and the target 5, while a film-thickness compensating shield 9, which is a film-thickness compensating shield surrounding the space and has a plurality of openings, is arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent conductive film forming method, and more particularly to a transparent conductive film forming method using a DC magnetron sputtering apparatus.

In recent years, liquid crystal displays have been required to be large-sized and colorized. In the manufacturing process of liquid crystal display panel,
Although there is a step of forming a transparent conductive film using AZO (or ITO) on a glass substrate, display unevenness is likely to occur due to high resistance on the surface of the transparent conductive film, resulting in a lower resistance and uniform resistance value distribution. A method for forming such a transparent conductive film is required.

[0003]

2. Description of the Related Art Conventionally, in the formation of a transparent conductive film using a DC magnetron sputtering apparatus, there is a problem that an erosion region is generated on a target when sputtering is performed, and the resistance value of the film at a substrate position facing it increases. there were.

Conventionally, this problem has been dealt with by increasing the thickness of the transparent conductive film to reduce the resistance value to zero. However, if the resistance value is decreased by increasing the film thickness, the problem that the light transmittance of the transparent conductive film is decreased and the light use efficiency is decreased, so that the transparent conductive film as thin as possible has a low resistance. The desire to achieve value is still great.

Further, in order to make the film thickness of the transparent conductive film uniform, a film thickness compensating shield is arranged in the sputtering device so as to surround the target to perform film formation. On the other hand, the installation of this film thickness compensation shield has the disadvantages that it reduces the exhaust efficiency around the target, tends to leave residual gas and impurities around the target, and delays reaching the target vacuum value.

[0006]

In view of the above problems, it is an object of the present invention to provide a method for reducing the resistance value and increasing the distribution of the resistance value without increasing the film thickness of the transparent conductive film. To do. Another object of the present invention is to provide a method for improving the exhaust characteristic in the sputtering apparatus without impairing the effect of the film thickness compensation shield.

[0007]

1 is a sectional view of a DC magnetron sputtering apparatus of the present invention, FIG. 2 is a perspective view of a shield plate, and FIG. 3 is a perspective view of a film thickness compensation shield.

[0008] The above problem is that when a transparent conductive film is formed on the substrate 1 by using the DC magnetron sputtering apparatus, a shield plate facing the erosion region 8 of the target 5 in the space between the substrate 1 and the target 5. This is solved by a transparent conductive film forming method of arranging 4 to form a film.

The shielding plate 4 can be solved by a method of forming a transparent conductive film comprising an inorganic shielding plate 4a and an organic coating film 4b deposited on the surface of the inorganic shielding plate 4a facing the target 5.

When a transparent conductive film is formed on the substrate 1 by using a DC magnetron sputtering device, the substrate 1
The shield plate 4 facing the erosion region 8 of the target 5 is arranged in the space between the target 5 and the target 5, and the film thickness compensation shield 9 surrounding the space is provided with the plurality of apertures 10. This is solved by a transparent conductive film forming method of disposing and forming a film.

[0011]

In the present invention, the shield plate 4 facing the erosion region 8 of the target 5 is arranged in the space between the substrate 1 and the target 5 to form a film. FIG. 5 is a view for explaining the action of the shield plate, and the shield plate 4 is arranged as the shield plate 4 so as to face the concentric erosion region 8.

Oxygen ions (O ⁻ ) from the erosion region 8 adversely affect the transparent conductive film (increase the resistance).
Negative ions 7 or impurities such as flutter out, but in order to prevent them from colliding with the glass substrate 1, the shielding plate 4 is arranged so as to face the erosion region 8 and the negative ions 7 are generated by the shielding plate 4.
Are either absorbed or reflected. This prevents the resistance value of the transparent conductive film formed on the glass substrate 1 facing the erosion region 8 from increasing.

Further, as shown in FIG. 2, the shielding plate 4 may be composed of an inorganic shielding plate (glass ring plate) 4a and an organic coating (PVA coating) 4b deposited on the surface facing the target 5. For example, the negative ions 7 or impurities jumping out from the erosion region 8 can be absorbed by the organic film 4b. After forming the transparent conductive film, the organic film 4b is peeled off from the glass ring plate 4a, and the organic film 4b is newly applied to the glass ring plate 4a at the time of forming the next transparent conductive film. A usable shield plate 4 can be realized. The organic coating 4b can be easily peeled from the inorganic shielding plate 4a by using, for example, an organic solvent.

Further, the film thickness compensating shield 9 surrounding the space between the glass substrate 1 and the target 5 is provided with a plurality of openings 10 as shown in FIG. It is possible to prevent residual gas and impurities from remaining around the target 5 and improve the speed of reaching the target vacuum value.

[0015]

1 is a cross-sectional view of a DC magnetron sputtering apparatus of the present invention, 1 is a glass substrate, 2 is a substrate holder,
3 is a magnet, 4 is a shield plate, 5 is a target, 6 is a shield plate, 8 is an erosion area, 9 is a film thickness compensation shield, and 11 is a target mounting base.

The glass substrate 1 is, for example, 30 mm × 100 mm,
Use 1.1 mm thick soda lime glass. The target 5 is made of, for example, a material in which 2.5 wt% of aluminum oxide (Al ₂ O ₃ ) is mixed in zinc oxide (ZnO) and has a diameter of 100.
A mm AZO circular target is used.

As the magnet 3, there are a cylindrical magnet arranged at the center and a ring-shaped magnet arranged on the circumference, and their polarities are opposite to each other. A shield plate 6 surrounding the magnet 3 is arranged from the periphery of the glass substrate 1, and a film thickness compensating shield 9 is arranged so as to surround the space between the target 5 and the glass substrate 1.

Since it was found that a ring-shaped erosion region 8 having an outer diameter of about 90 mm and an inner diameter of about 70 mm was formed on the target 5, the shield plate 4 was formed correspondingly.
FIG. 2 is a perspective view of the shield plate. The glass ring plate 4a is made of, for example, 1.1 mm thick soda lime glass and has an outer diameter of 90 mm.
mm, inner diameter 70 mm. The organic film 4b is formed, for example, by coating PVA (polyvinyl alcohol) on the glass ring plate 4a and heating it at a temperature higher than the film forming temperature, for example, 250
Bake at ℃.

FIG. 3 is a perspective view of the film thickness compensation shield.
The film thickness compensating shield 9 uses a permalloy plate with a plurality of holes formed, and is a square with one side of 130 mm, for example.
The frame is formed with a height of 30 mm. The size and number of openings are determined by the balance between shielding and exhausting. That is, when the size of the openings is large and the number thereof is large, the exhaust performance is improved, but the shielding property is deteriorated. Therefore, the size and the number of the openings are determined in advance by experiments.

The shield plate 4 shown in FIG. 2 is arranged on the target 5 at a distance of 20 mm, and the film thickness compensation shield 9 shown in FIG. 3 is arranged on the shield plate 6 between the glass substrate 1 and the target 5. The glass substrate 1 was arranged so as to surround the space, and the distance between the glass substrate 1 and the target 5 was 75 mm. The target vacuum value was 3 × 10 ^-6 Torr, and the time to reach it was 26 minutes. Incidentally, the time required when the conventional film thickness compensating shield having no aperture was arranged was 31 minutes.

An introduction gas Ar, an input power of 2 kW, and a sputtering gas pressure of 5 × 10 ⁻³ Pa were adopted as sputtering conditions, and an AZO film having a thickness of 300 nm was formed on the glass substrate 1 at a film forming time of 11.5 minutes.

FIG. 4 is a diagram showing the distribution of resistivity of the formed transparent conductive film, and for comparison, also shows a conventional example in which no shielding plate is arranged. As shown in Fig. 4, when the shielding plate is placed, the resistivity ρ is 5 within 5 cm from the center of the substrate.
Although it shows a uniform distribution of about 10 ^-4 Ω · cm, the resistivity ρ is about 5 × 10 ^-4 Ω · cm within 3 cm from the center of the substrate without a shield plate. Although it is uniform, the resistivity increases several times in the region of 3 to 5 cm from the substrate center.

By thus disposing the shielding plate, a uniform transparent conductive film having a low resistivity can be formed on the glass substrate 1. When the shielding plate 4 is used next time, the organic coating 4b is immersed in, for example, an organic solvent to be peeled off, and the organic coating 4b is newly formed as described above. By doing so, it is possible to always use the same shielding plate 4 as a new one, and it is possible to maintain the effect as the shielding plate 4.

[0024]

As described above, according to the present invention,
By disposing the shielding plate 4 between the target 5 and the glass substrate 1 so as to face the erosion region 8 and forming a transparent conductive film, a transparent conductive film having a uniform resistivity even if the film thickness is thin, for example, about 300 nm. A film can be formed.

Further, by using the inorganic shielding plate 4a on which the organic coating 4b is formed as the shielding plate 4, the organic coating 4b can be easily formed and removed. If the organic film 4b is formed every time the sputtering for forming the transparent conductive film is performed, the same effect as that of the new shielding plate 4 can be maintained.

Further, by providing the hole 10 in the film thickness compensation shield 9, it is possible to easily remove the residual gas and impurities around the target 5 and easily reach the target vacuum value.

[Brief description of drawings]

FIG. 1 is a sectional view of a DC magnetron sputtering apparatus of the present invention.

FIG. 2 is a perspective view of a shield plate.

FIG. 3 is a perspective view of a film thickness compensation shield.

FIG. 4 is a diagram showing a distribution of resistivity of a transparent conductive film.

FIG. 5 is a view for explaining the action of the shield plate.

[Explanation of symbols]

 1 is a substrate, 2 is a glass substrate, 2 is a substrate holder, 3 is a magnet, 4 is a shielding plate, 4a is an inorganic shielding plate, and 4g is an organic film, PVA film is a target, 6 is a shield plate, 7 is a negative ion. 8 is an erosion area 9 is a film thickness compensation shield 10 is an opening 11 is a target mount

Claims (3)

[Claims] 1. When forming a transparent conductive film on a substrate (1) using a DC magnetron sputtering apparatus, the substrate (1)
A film forming method for a transparent conductive film, comprising: disposing a shielding plate (4) facing an erosion region (8) of the target (5) in a space between the target and the target (5). 2. The shielding plate (4) comprises an inorganic shielding plate (4a) and an organic coating (4b) deposited on the surface of the inorganic shielding plate (4a) facing the target (5). The method for forming a transparent conductive film according to claim 1, wherein the transparent conductive film is formed. 3. When forming a transparent conductive film on a substrate (1) by using a DC magnetron sputtering apparatus, the substrate (1)
A shield plate (4) facing the erosion region (8) of the target (5) is placed in the space between the target and the target (5), and there is a film thickness compensation shield surrounding the space and a plurality of apertures ( Ten)
A method for forming a transparent conductive film, which comprises arranging a film thickness compensation shield (9) having